/BACKSPACE=keyword

    Controls how the system responds to the backspace key (Ctrl/H) in
    line editing mode. There are two possible keywords:

    o  BACKSPACE (default) - The terminal driver returns the user
       to the beginning of the line. (This is the traditional way
       OpenVMS has always worked.)

    o  DELETE - The terminal driver interprets the backspace key as a
       delete character instruction.

       Note the following exceptions:

       -  If the terminal is set in PASSALL or PASTHRU mode, the
          backspace key is not interpreted as a delete character
          instruction.

       -  If the user issues an IO$_READVBLK with IO$M_NOFILTR or
          IO$_READPBLK, the backspace key is not interpreted as a
          delete character instruction.

    You can use SYSGEN to make /BACKSPACE=DELETE the default for all
    terminals by setting the system parameter TTY_DEFCHAR3 to 16.

    If the default is set to DELETE, the user can still go to the
    start of a line by pressing F12 or by entering the following
    sequence: Ctrl/V Ctrl/H Ctrl/H.

    If you use SET HOST, both the local node and the remote node must
    be capable of responding to your definition of the BACKSPACE key.